1. Field of the Invention
The present invention relates generally to devices incorporating a source of light, and more particularly to a light source including to a lens cover or lamp cover manufactured from a sol-gel type material such as glass or quartz, which includes integral a surface diffuser which homogenizes, controls the direction of, and shapes light from the source with high transmission efficiency.
2. Description of the Related Art
Lighting technology continues to improve in many areas in lighting design to reduce the size of the devices as well as to increase light source efficiency and longevity. Many more recent light sources and designs provide greater amounts of light for longer periods of time and come in smaller packages when compared to lights of several years ago. These improved light sources however, generate much more heat during operation which can cause damage to objects surrounding the light sources as well as components attached to the light source.
Therefore, in designing light sources for many applications, the housing structures surrounding the light sources, the products utilized to direct light emanating from the source, and all other components added to the light source for a desired aesthetic appearance must all be designed to withstand the heat generated by these light sources. Additionally, many of these lights are designed for use under environmental conditions which are extremely harsh and that can damage many of the surrounding components associated with the light source assembly.
Examples of use for new light sources are projector lamps, automotive headlamps, table lamps, floor lamps, and architectural lighting systems utilizing halogen bulb technology and high watt/high temperature lasers. Exterior lighting for street lights, area lights for building grounds, lighting for airports and runways, and even lighting for many indoor and outdoor facilities such as sports arenas, stage, studio, and parks are starting to utilize halogen technology and low pressure arc lamps (X.sub.c example) as well as other alternative light sources which generate extreme heat. For example, a relatively new lighting source has a small amount of sulfur and an inert argon gas within a bulb that is bombarded with microwave energy to produce a significant amount of light from a relatively small source that lasts for a long time. This type of bulb generates extreme amounts of heat.
In lighting industries, it is very common to include a lens cover adjacent the light source to improve the aesthetic appearance of the light as well as to somewhat diffuse the light emanating from the source. Such covers have traditionally been made from durable materials such as glass or less durable materials such as plastics which can withstand only so much heat. In high power laser applications the energy or power is so great that plastic materials and some glass materials will melt or shatter.
An additional problem with most of these light sources is that the light directing capabilities and the light diffusing capabilities are accomplished by substantially rudimentary technology or not at all. Much of the light emanating from these light sources is not fully utilized or is wasted and not directed toward a desired object or area and is not "shaped" to properly illuminate that area. Additionally, virtually all of these light sources produce a light output pattern in a somewhat uneven, discontinuous manner. Therefore, within a particular pattern or distribution of light emanating from the source, there are high intensity spots containing more light and low intensity spots containing less light. The rudimentary diffusing capabilities do not direct, shape or spread the light at all and are rather poor in providing an even and smooth distribution of light.
Currently, there are very few diffusing, light shaping or even substrated that will transmit the UV down to and below 200 nm. In photolithography and other UV light applications such as in the medical field, there is a tremendous need for highly transmissive diffusion and beam shaping.
The assignee of the present invention has invented a number of methods for producing a light diffusing and directing micro-sculpted surface structure on a substrate. These methods and apparatuses are disclosed in a number of issued patents assigned to the assignee of the present invention as well as a number of co-pending U.S. Patent Applications also assigned to the assignee of the present invention.
For example, methods for manufacturing and replicating optical components such as a master diffuser exhibiting desired light diffusing characteristics are well known. Many of these methods involve creating a master diffuser by exposing a photoresist material to a source of light and then replicating this master diffuser into one or more submasters of a more durable nature. There are also other methods of making replicas of a master diffuser which contain the optical features in the master. With each of these methods, the master diffuser is initially created optically. Submasters are created from these master diffusers utilizing a number of methods whereby the master diffuser surface is replicated into a submaster surface. These other methods are described in one or more pending U.S. applications, referenced below, which are assigned to the assignee of the present invention.
The following commonly assigned U.S. patents and pending applications disclose related methods for making and recording optical products and replicating those products so that they may be mass produced. For example, U.S. Pat. No. 5,365,354 entitled "Grin Type Diffuser Based on Volume Holographic Material," U.S. Pat. No. 5,534,386 entitled "Homogenizer Formed Using Coherent Light and a Holographic Diffuser," and U.S. Pat. No. 5,609,939 entitled "Viewing Screen Formed Using Coherent Light," all owned by the present assignee relate to methods for recording and replicating optical products. Each of these U.S. patents is incorporated herein by reference for purposes including, but not limited to, indicating the background of the present invention and illustrating the state of the art.
Related co-pending U.S. patent applications include Ser. No. 09/052,586 entitled "Method of Making Replicas While Preserving Master," Ser. No. 08/595,307 entitled "LCD With Light Source Destructuring and Shaping Device," Ser. No. 08/782,962 entitled "Apparatus for LCD Backlighting," Ser. No. 08/618,539 entitled "Method of Making Liquid Crystal Display System," Ser. No. 08/800,872 entitled "Method of Making Replicas and Compositions for Use Therewith," and Ser. No. 09/075,023 entitled "Method and Apparatus for Making Optical Masters Using Incoherent Light," Ser. No. 08/902,415 entitled "Monolithic Glass Light Shaping Diffuser and Method for Its Production," and "Non-Lambertian Glass Diffuser and Method of Making," filed Aug. 20, 1998, "Diffuser Master and Method of Manufacture," filed Aug. 20, 1998, "High Efficiency Monolithic Glass Light Shaping Diffuser and Method of Making," filed Aug. 25, 1998, "Optical Element Having an Integral Surface Diffuser," filed Aug. 25, 1998, "Vehicle Light Assembly Including a Diffuser Surface Structure," filed Aug. 25, 1998, "Passive Matrix Liquid Crystal Display," filed Aug. 25, 1998, and "Device Including an Optical Element With a Diffuser," filed Aug. 25, 1998. All the above applications are owned by the present assignee and are hereby incorporated by reference for purposes including, but not limited to, indicating the background of the present invention and illustrating the state of the art.
In addition, the assignee of the present invention has invented a number of methods for forming a diffuser structure from a substantially durable and high temperature resistant glass or optical material. The glass is cured from a sol-gel solution. A surface of the cured sol-gel glass includes an integral diffuser micro-sculpted surface structure capable of both homogenizing light passing through the glass diffuser as well as controlling directionality of the light within a particular pattern and direction. These apparatuses and methods are disclosed in the above incorporated co-pending U.S. Patent Applications recently filed in the U.S. Patent and Trademark Office. The methods include replicating the surface structure from a rubber submaster or other submaster which was previously recorded optically from a master. The surface structure can also be created mechanically by brushing, blasting or etching a surface of the sol-gel glass.